The present invention relates to a method of preparing a conductive polymer material for an electrode and a method of forming an electrode using a conductive polymer material, and more particularly to a method of producing a conductive material suitable for a mass-synthesis thereof at a high yield and a method of forming an electrode at a high productivity.
A conductive material has been developed which is to be formed on a surface of an electrode for a secondary battery or a capacitor. The conductive polymer material has been prepared as follows. FIG. 1 is a view illustrative of a conventional method of preparing the conductive polymer material. An organic compound 2 is dissolved into an electrolytic solution 3, wherein the organic compound 2 comprises a monomer or a low molecular weight polymer of organic molecules which have a skeleton allowing formation of a conductive polymer material. A collector 1 is dipped into the electrolytic solution 3 dissolved with the organic compound 2 in order to cause an electrolytic polymerization of the above monomers or the above low molecular weigh, thereby obtaining a conductive polymer material. If the obtained conductive polymer material is soluble to the electrolytic solution, the conductive polymer material dissolved in the electrolytic solution is then subjected to a solvent extraction so as to isolate the conductive polymer material from the electrolytic solution.
The conventional method of producing the conductive polymer material has the following problems. The organic compound 2 shows a reaction on the collector 1. In this reaction, a diffusion process is caused where the organic compound 2 is diffused in the electrolytic solution 3 up to the collector 1. A diffusion rate or a diffusion speed depends upon the organic compound 2 and a solvent of the electrolytic solution 3. In general, the diffusion rate is slow and is a rate-determining step of polymerization. The rate of the polymerization depends upon a concentration of the organic compound 2. If a solubility of the organic compound to the solvent of the electrolytic solution 3 is low, it is difficult to obtain a high concentration of the organic compound 2 in the electrolytic solution 3, for which reason a current density in polymerization process or a polymerization current density is low, whereby it is difficult to obtain a high productivity or a high yield of polymerization. Namely, the conventional method is engaged with the problem in low polymerization yield in the electrolytic polymerization.
The above conventional method illustrated in FIG. 1 has a further problem as follows. An amount of the organic compound 2 soluble into the solvent for the electrolytic solution 3 is limited. Namely, the organic compound 2 has a maximum solubility into the solvent for the electrolytic solution 3. If the maximum solubility of the organic compound 2 into the solvent for the electrolytic solution 3 is low, then it is difficult to realize a moss-synthesis.
Consequently, the conventional method of producing the conductive polymer is disadvantageous in low yield and low productivity, and a difficulty in mass-synthesis.
In the above circumstances, it had been required to develop a novel method of producing a conductive polymer free from the above problem.